Abstract

The spectral density of plasma waves generated at the ‐type magnetic neutral point of a laboratory device known as the double inverse pinch has been measured using a double probe technique devised by Hamberger and Jancarik. The spectra peak at low frequencies and have no components above the ion plasma frequency. This is in general agreement with the ion‐acoustic wave spectrum of Kadomtsev. No contribution is seen at frequencies characteristic of the two‐stream instability. The plasma wave amplitude is estimated to be sufficient to produce the anomalous resistivity which has been observed in this device. A knowledge of the resistivity mechanism is essential in understanding neutral point phenomenon as the resistivity controls “the reconnection rate” or more precisely the flux transfer rate. Flux transfer is almost certainly a key element of solar flares and geomagnetic substorms. The flux transfer process also occurs in many laboratory plasma experiments.